Retention and post-treatment stability in the adult dentition.

Post-treatment changes that occur in the supporting apparatus must be considered in the design and time of use of retention devices. Of equal importance is establishing the methodology of retention prior to initiating active orthodontic therapy. The different types of retainers that are best used are reviewed.

Chronic necrotizing pulmonary aspergillosis: a discrete clinical entity.

We conclude that chronic necrotizing pulmonary aspergillosis is a clinical entity which has not usually been recognized as one of the forms of pulmonary disease due to Aspergillus species. Patients are middle-aged, and often have some evidence of impairment of host defenses such as diabetes mellitus, a connective tissue disorder, poor nutrition, chronic obstructive lung disease or low dose corticosteroid therapy. They are almost always symptomatic with fever and a productive cough, and their chest roentgenogram shows infiltrative and cavitary disease, typical of a chronic destructive lung process such as tuberculosis or anaerobic infection. Cavity formation is often accompanied by the development of a mycetoma. The disease is usually of 1 to 6 months duration but can be present for years prior to diagnosis. The diagnosis is suggested by the clinical course and the isolation of the fungus from pulmonary secretions; negative cultures for other pathogens and failure to respond to antibacterial or antimycobacterial therapy are characteristic. The diagnosis is confirmed by pathologic evidence of tissue invasion by the fungus or a response to specific antimycotic therapy. The symptomatic response to antifungal chemotherapy, at times combined with surgical drainage or resection, is favorable. However, roentgenographic resolution is not uniform, and many patients have residual cavitary disease. The long-term prognosis is uncertain.

Diagnosis of posterior mediastinal goiter by computed tomography.

Although radionuclide examinations are usually diagnostic for evaluating mediastinal goiters, false negative examinations do occur, and the diagnosis may not be suspected based on clinical or radiographic features. In such a setting, computed tomography (CT) may demonstrate both anatomic and physiologic evidence of thyroid mass, providing useful diagnostic information. We report a case in which CT derived data aided in an early diagnosis of mediastinal gioter.

Lung function among black and white children.

Racial differences in ventilatory lung function were evaluated in a community study of 393 children (158 blacks, 235 whites). Mean forced vital capacity was 18 per cent larger in nonsmoking white males than in nonsmoking black males, and 11 per cent larger in nonsmoking white females than in nonsmoking black females. Similar differences were observed for the 1-sec forced expiratory volume and for the maximal expiratory flow at 50 per cent of the vital capacity. However, when adjusted for lung size (on the basis of forced vital capacity), 1-sec forced expiratory volume and maximal expiratory flow at 50 per cent of the forced vital capacity were larger in the black children compared to the white children. Lung function prediction equations based on race, sex, age, height and weight are presented for healthy nonsmoking children; these allow for an evaluation of normal lung function in both black and white children.

Importance of the indoor environment in air pollution exposure.

A portable personal air pollution sampler was used to measure the exposure of twenty children to respirable particulates, sulfur dioxide, and nitrogen dioxide over a 24-hour period. Particulate exposures were significantly higher among children who lived with one or more smokers, and exceeded the primary air quality standard in nineteen of the twenty subjects. To a large extent, an individual's respirable particulate load appears to be determined by exposure to indoor rather than outdoor pollutants.

Use of the productive cough test to confirm presence of respiratory symptoms in school-age children.

We assessed the prevalence of respiratory symptoms and loose cough in 622 school-age children from an urban town in Connecticut. A higher prevalence of chronic symptoms was reported by black children, but the prevalence of recent symptoms and of loose cough in black children was similar to that in white children. The relationship between prevalence of recent symptoms and loose cough suggests that the observed racial differences in prevalence of chronic symptoms were unlikely to be due to racial differences in responses to a respiratory symptom questionnaire.